Developing Automatic Lens Module Assembly System Using 3D Simulation

문덕희,이준석,백승근,장병림,김영규,Moon, Dug-Hee,Lee, Jun-Seok,Baek, Seung-Geun,Zhang, Bing-Lin,Kim, Yeong-Gyoo The Korea Society for Simulation 2007 한국시뮬레이션학회 논문지 Vol.16 No.2

Virtual manufacturing (VM) is a powerful technology for developing a new product, new equipment and new manufacturing system, and three-dimensional (3D) simulation is a core technology in VM. 3D simulation involves both mechanical simulation and discrete event simulation. This paper introduces a case study of implementing 3D simulation for developing an automatic assembly line in a Korean optical factory. This factory produces a lens module that is the part of a phone-camera. 3D simulation technology is applied from the early stage of development. In the conceptual design and the initial design phases for individual equipment, 3D mechanical simulation using $CATIA^{(R)}$ and $IGRIP^{(R)}$ is conducted. 3D discrete event simulation with $QUEST^{(R)}$ is applied to the detailed design of the equipment and of the whole system. The focus of the simulation is to verify the technical and economical feasibility of the new automatic system. As a result, the takt time is reduced to the quarter of the manual system, and the number of workers in a line is reduced tremendously.

Output Data Analysis of Simulation: A Review

장병윤,Chang, Byeong-Yun The Korea Society for Simulation 2012 한국시뮬레이션학회 논문지 Vol.21 No.3

Simulation is the imitation of the operation of a real-world process or system over time. It concerns the study of the operating characteristics of real systems. Typically, a simulation project consists of several steps such as data collection, coding, model verification, model validation, experimental design, output data analysis, and implementation. Among these steps of a simulation study this paper focus on statistical analysis methods of simulation output data. Specially, we explain how to develop confidence interval estimators for mean ${\mu}$ in terminating and non-terminating simulation cases. We, then, explore the estimation techniques for $f({\mu})$, where the function $f({\bullet})$ is a nonlinear that is continuously differentiable in a neighborhood of ${\mu}$ with $f'({\mu}){\neq}0$.

Application of Control Variable with Routing Probability to Queueing Network Simulation

권치명,임상규,Kwon, Chi-Myung,Lim, Sang-Gyu The Korea Society for Simulation 2012 한국시뮬레이션학회 논문지 Vol.21 No.3

This research discusses the application of the control variables to achieve a more precise estimation for the target response in queueing network simulation. The efficiency of control variable method in estimating the response depends upon how we choose a set of control variables strongly correlated with the response and how we construct a function of selected control variables. For a class of queuing network simulations, the random variables that drive the simulation are basically the service-time and routing probability random variables. Most of applications of control variable method focus on utilization of the service time random variables for constructing a controlled estimator. This research attempts to suggest a controlled estimator which uses these two kinds of random variables and explore the efficiency of these estimators in estimating the reponses for computer network system. Simulation experiments on this model show the promising results for application of routing probability control variables. We consider the applications of the routing probability control variables to various simulation models and combined control variables using information of service time and routing probability together in constructing a control variable as future researches.

Application of the BMORE Plot to Analyze Simulation Output Data with Bivariate Performance Measures

이미림,이진표,박민재,Lee, Mi Lim,Lee, Jinpyo,Park, Minjae The Korea Society for Simulation 2020 한국시뮬레이션학회 논문지 Vol.29 No.2

Bivariate measure of risk and error(BMORE) plot is originally designed to depict bivariate output data and related statistics obtained from a stochastic simulation such as sample mean, median, outliers, and a boundary of a certain percentile of simulation data. When compared to the static numbers, the plot has a big advantage in visualization that enables scholars and practitioners to understand the potential variability and risk in the simulation data. In this study, beyond just the construction of the plot to depict the variability of a certain system, we add a chance constraint to the plot and apply it for decision making such as checking the feasibility of systems, comparing performances of the systems on statistical background, and also analyzing the sensitivity of the problem parameters. In order to demonstrate an application of the plot, we employ an inventory management problem as an example. However, the techniques and algorithms suggested in this paper can be applied to any other problems comparing systems on bivariate performance measures with simulation/experiment results.

Variance Reduction via Adaptive Control Variates (ACV)

Lee, Jae-Yeong The Korea Society for Simulation 1996 한국시뮬레이션학회 논문지 Vol.5 No.1

Control Variate (CV) is very useful technique for variance reduction in a wide class of queueing network simulations. However, the loss in variance reduction caused by the estimation of the optimum control coefficients is an increasing function of the number of control variables. Therefore, in some situations, it is required to select an optimal set of control variables to maximize the variance reduction . In this paper, we develop the Adaptive Control Variates (ACV) method which selects an optimal set of control variates during the simulation adatively. ACV is useful to maximize the simulation efficiency when we need iterated simulations to find an optimal solution. One such an example is the Simulated Annealing (SA) because, in SA algorithm, we have to repeat in calculating the objective function values at each temperature, The ACV can also be applied to the queueing network optimization problems to find an optimal input parameters (such as service rates) to maximize the throughput rate with a certain cost constraint.

A Study on the Battle Management Language Application for the C4I and M&S Interoperation in ROK Forces

정환식,이재영,Jung, Whan-Sik,Lee, Jae-Yeong The Korea Society for Simulation 2010 한국시뮬레이션학회 논문지 Vol.19 No.1

Battle Management Language (BML) is defined as an unambiguous language intended to provide for command and control of simulated and live forces in U.S. It has been developed to connect between command and control system and Modeling & Simulation in the U.S., including NATO M&S Working Group. Its goal is to provide situational awareness and offer a path forward for interoperation of C2 systems and simulations. This study deals with BML development in U.S. that begins from army and is being expanded in multinational environment. It also proposes the BML application for C4I and M&S interoperation in the Korean forces. Recent developments of BML in U.S. have shown the potential for interoperation between C2 systems and simulations in a coalition environment. Finally, this study proposes a general BML application method and shows the example of its application to the Korea Joint Command Control System (KJCCS). It provides an architecture and a milestone for BML application in the Korean forces.

Design Methodology of System-Level Simulators for Wideband CDMA Cellular Standards

박성경,Park, Sungkyung The Korea Society for Simulation 2013 한국시뮬레이션학회 논문지 Vol.22 No.1

This tutorial paper presents the design methodology of system-level simulators targeted for code division multiple access (CDMA) cellular standards such as EV-DO (Evolution-Data Only) and broadcast multicast service (BCMCS). The basic structure and simulation flow of system-level simulators are delineated, following the procedure of cell layout, mobile drops, channel modeling, received power calculation, scheduling, packet error prediction, and traffic generation. Packet data transmissions on the forward link of CDMA systems and EV-DO BCMCS systems are considered for modeling simulators. System-level simulators for cellular standards are modeled and developed with high-level languages and utilized to evaluate and predict air interface performance metrics including capacity and coverage.

A Fuzzy Logic-Based False Report Detection Method in Wireless Sensor Networks

김문수,이해영,조대호,Kim, Mun-Su,Lee, Hae-Young,Cho, Tae-Ho The Korea Society for Simulation 2008 한국시뮬레이션학회 논문지 Vol.17 No.3

Wireless sensor networks are comprised of sensor nodes with resource-constrained hardware. Nodes in the sensor network without adequate protection may be compromised by adversaries. Such compromised nodes are vulnerable to the attacks like false reports injection attacks and false data injection attacks on legitimate reports. In false report injection attacks, an adversary injects false report into the network with the goal of deceiving the sink or the depletion of the finite amount of energy in a battery powered network. In false data injection attacks on legitimate reports, the attacker may inject a false data for every legitimate report. To address such attacks, the probabilistic voting-based filtering scheme (PVFS) has been proposed by Li and Wu. However, each cluster head in PVFS needs additional transmission device. Therefore, this paper proposes a fuzzy logic-based false report detection method (FRD) to mitigate the threat of these attacks. FRD employs the statistical en-route filtering scheme as a basis and improves upon it. We demonstrate that FRD is efficient with respect to the security it provides, and allows a tradeoff between security and energy consumption, as shown in the simulation.

Performance Analysis of DoS/DDoS Attack Detection Algorithms using Different False Alarm Rates

장범수,이주영,정재일,Jang, Beom-Soo,Lee, Joo-Young,Jung, Jae-Il The Korea Society for Simulation 2010 한국시뮬레이션학회 논문지 Vol.19 No.4

Internet was designed for network scalability and best-effort service which makes all hosts connected to Internet to be vulnerable against attack. Many papers have been proposed about attack detection algorithms against the attack using IP spoofing and DoS/DDoS attack. Purpose of DoS/DDoS attack is achieved in short period after the attack begins. Therefore, DoS/DDoS attack should be detected as soon as possible. Attack detection algorithms using false alarm rates consist of the false negative rate and the false positive rate. Moreover, they are important metrics to evaluate the attack detections. In this paper, we analyze the performance of the attack detection algorithms using the impact of false negative rate and false positive rate variation to the normal traffic and the attack traffic by simulations. As the result of this, we find that the number of passed attack packets is in the proportion to the false negative rate and the number of passed normal packets is in the inverse proportion to the false positive rate. We also analyze the limits of attack detection due to the relation between the false negative rate and the false positive rate. Finally, we propose a solution to minimize the limits of attack detection algorithms by defining the network state using the ratio between the number of packets classified as attack packets and the number of packets classified as normal packets. We find the performance of attack detection algorithm is improved by passing the packets classified as attacks.

Automating Model Building Processes for Simulation of Complex Manufacturing and Logistics Systems

서정훈,김갑환,Seo, Jeong Hoon,Kim, Kap Hwan The Korea Society for Simulation 2018 한국시뮬레이션학회 논문지 Vol.27 No.2

Simulations have been used to evaluate the efficiency of logistics or manufacturing systems and predict the outcomes of the systems. New simulation models are needed to evaluate new alternative plants and layouts during the resource design process. Although it is easy to handle minor changes in parameters by modifying a simulation model, it takes considerable time and effort for simulation modelers to alter the layout, which involves changes in many simulation sub-models. Therefore, this study proposes a method to transfer information in AutoCAD layout to the simulation model automatically. This study also defines a standard document as an Excel Form, and suggests a method to transfer information on the basic layouts, processes, resources, and workers to a simulation model automatically. A simulation tool, called Tecnomatix Plant Simulation 9.0, was used for this study. The proposed approach in this study was applied to a semiconductor wafer factory for a case study.